cop·​per·​as ˈkä-p(ə-)rəs How to pronounce copperas (audio)

Word History


Middle English coperas, from Anglo-French coperose, from Medieval Latin cuprosa, probably from aqua cuprosa, literally, copper water, from Late Latin cuprum

First Known Use

14th century, in the meaning defined above

Time Traveler
The first known use of copperas was in the 14th century

Dictionary Entries Near copperas

Cite this Entry

“Copperas.” Dictionary, Merriam-Webster, Accessed 23 Feb. 2024.

Medical Definition


cop·​per·​as ˈkäp-(ə-)rəs How to pronounce copperas (audio)
: a green hydrated ferrous sulfate FeSO4·7H2O used especially in making inks and pigments
used especially of commercial grades not to be used internally
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!